Assessment of Ki67 and uPA/PAI-1 expression in intermediate-risk early stage breast cancers

Independent validation of stromal uPA in ABCSG-08: Level 1b evidence for the prognostic value of uPA immunohistochemistry

Purpose

Patients and methods

Results

Conclusion

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Prospective trial provides level 1b evidence.

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UPA expression associated with better DDFS and OS.

Breast Cancer 18F-ISO-1 Uptake as a Marker of Proliferation Status

The σ₂ receptor is a potential in vivo target for measuring proliferative status in cancer. The feasibility of using N-(4-(6,7-dimethoxy-3,4-dihydroisoquinolin-2(1H)-yl)butyl)-2-(2-¹⁸F-fluoroethoxy)-5-methylbenzamide (¹⁸F-ISO-1) to image solid tumors in lymphoma, breast cancer, and head and neck cancer has been previously established. Here, we report the results of the first dedicated clinical trial of ¹⁸F-ISO-1 in women with primary breast cancer. Our study objective was to determine whether ¹⁸F-ISO-1 PET could provide an in vivo measure of tumor proliferative status, and we hypothesized that uptake would correlate with a tissue-based assay of proliferation, namely Ki-67 expression. Methods: Twenty-eight women with 29 primary invasive breast cancers were prospectively enrolled in a clinical trial (NCT02284919) between March 2015 and January 2017. Each received an injection of 278-527 MBq of ¹⁸F-ISO-1 and then underwent PET/CT imaging of the breasts 50-55 min later. In vivo uptake of ¹⁸F-ISO-1 was quantitated by SUV_max and distribution volume ratios and was compared with ex vivo immunohistochemistry for Ki-67. Wilcoxon rank-sum tests assessed uptake differences across Ki-67 thresholds, and Spearman correlation tested associations between uptake and Ki-67. Results: Tumor SUV_max (median, 2.0 g/mL; range, 1.3-3.3 g/mL), partial-volume-corrected SUV_max, and SUV ratios were tested against Ki-67. Tumors stratified into the high-Ki-67 (≥20%) group had SUV_max greater than the low-Ki-67 (<20%) group (P = 0.02). SUV_max exhibited a positive correlation with Ki-67 across all breast cancer subtypes (ρ = 0.46, P = 0.01, n = 29). Partial-volume-corrected SUV_max was positively correlated with Ki-67 for invasive ductal carcinoma (ρ = 0.51, P = 0.02, n = 21). Tumor-to-normal-tissue ratios and tumor distribution volume ratio did not correlate with Ki-67 (P > 0.05). Conclusion: ¹⁸F-ISO-1 uptake in breast cancer modestly correlates with an in vitro assay of proliferation.

Levels of uPA and PAI-1 in breast cancer and its correlation to Ki67-index and results of a 21-multigene-array

Background

Conventional parameters including Ki67, hormone receptor and Her2/neu status are used for risk stratification for breast cancer. The serine protease urokinase plasminogen activator (uPA) and the plasminogen activator inhibitor type-1 (PAI-1) play an important role in tumour invasion and metastasis. Increased concentrations in tumour tissue are associated with more aggressive potential of the disease. Multigene tests provide detailed insights into tumour biology by simultaneously testing several prognostically relevant genes. With OncotypeDX®, a panel of 21 genes is tested by means of quantitative real-time polymerase chain reaction.

The purpose of this pilot study was to analyse whether a combination of Ki67 and uPA/PAI-1 supplies indications of the result of the multigene test.

Methods

The results of Ki67, uPA/PAI-1 and OncotypeDX® were analysed in 25 breast carcinomas (luminal type, pT1/2, max pN1a, G2). A statistical and descriptive analysis was performed.

Results

With a proliferation index Ki67 of < 14%, the recurrence score (RS) from the multigene test was on average in the low risk range, with an intermediate RS usually resulting if Ki67 was > 14%. Not elevated values of uPA and PAI-1 showed a lower rate of proliferation (average 8.5%) than carcinomas with an increase of uPA and/or PAI-1 (average 13.9%); p = 0.054, Student’s t-test. When Ki67 was > 14% and uPA and/or PAI-1 was raised, an intermediate RS resulted. These differences were significant when compared to cases with Ki67 < 14% with non-raised uPA/PAI-1 (p < 0.03, Student’s t-test). Without taking into account the proliferative activity, an intermediate RS was also verifiable if both uPA and PAI-1 showed raised values.

Conclusion

A combination of the values Ki67 and uPA/PAI-1 tended to depict the RS to be expected. From this it can be deduced that an appropriate analysis of this parameter combination may be undertaken before the multigene test in routine clinical practice. The increasing cost pressure makes it necessary to base the implementation of a multigene test on ancillary variables and to potentially leave it out if not required in the event of a certain constellation of results (Ki67 raised, uPA and PAI-1 raised).